Harry Truman’s Decision to Use the Atomic Bomb

The Decision

Aerial view of Hiroshima depicts the terrific destructive force of the atomic bomb
Aerial view of Hiroshima depicts the terrific destructive force of the atomic bomb

United States Army Air Corps; Harry S. Truman Library & Museum

By August, 1945, Japan had lost World War II.  Japan and the United States both knew it.  How long would it be, however, before Japan surrendered?  Japan was split between surrender or fighting to the end.  They chose to fight.

In mid-July, President Harry S Truman was notified of the successful test of the atomic bomb, what he called “the most terrible bomb in the history of the world.”  Thousands of hours of research and development as well as billions of dollars had contributed to its production.  This was no theoretical research project.  It was created to destroy and kill on a massive scale.  As president, it was Harry Truman’s decision if the weapon would be used with the goal to end the war.  “It is an awful responsibility that has come to us,” the president wrote.

President Truman had four options:  1) continue conventional bombing of Japanese cities; 2) invade Japan; 3) demonstrate the bomb on an unpopulated island; or, 4) drop the bomb on an inhabited Japanese city.

Option 1: Conventional Bombing of the Japanese Home Islands

While the United States began conventional bombing of Japan as early as 1942, the mission did not begin in earnest until mid-1944.  Between April 1944 and August, 1945, an estimated 333,000 Japanese people were killed and 473,000 more wounded in air raids.  A single firebombing attack on Tokyo in March 1945 killed more than 80,000 people.  Truman later remarked, “Despite their heavy losses at Okinawa and the firebombing of Tokyo, the Japanese refused to surrender.  The saturation bombing of Japan took much fiercer tolls and wrought far and away more havoc than the atomic bomb.  Far and away.  The firebombing of Tokyo was one of the most terrible things that ever happened, and they didn't surrender after that although Tokyo was almost completely destroyed.”

In August 1945, it was clear that conventional bombing was not effective.

Option 2: Ground Invasion of the Japanese Home Islands

The United States could launch a traditional ground invasion of the Japanese home islands.  However, experience showed that the Japanese did not easily surrender.  They had been willing to make great sacrifices to defend the smallest islands.  They were likely to fight even more fiercely if the United States invaded their homeland.  During the battle at Iwo Jima in 1945, 6,200 US soldiers died.  Later that year, on Okinawa, 13,000 soldiers and sailors were killed.  Casualties on Okinawa were 35 percent; one out of three US participants was wounded or killed.  Truman was afraid that an invasion of Japan would look like "Okinawa from one end of Japan to the other."  Casualty predictions varied, but all were high.  The price of invasion would be millions of American dead and wounded.

Estimates did not include Japanese casualties.  Truman and his military advisers assumed that a ground invasion would “be opposed not only by the available organized military forces of the Empire, but also by a fanatically hostile population."   Documents discovered after the war indicated that they were right.  Despite knowing the cause was hopeless, Japan planned a resistance so ferocious, resulting in costs so appalling, that they hoped that the United States would simply call for a cease fire where each nation would agree to stop fighting and each nation would retain the territory they occupied at the time.  Almost one-quarter million Japanese casualties were expected in the invasion.  Truman wrote, “My object is to save as many American lives as possible but I also have a human feeling for the women and children of Japan.” 

In August 1945, it appeared inevitable that Japanese civilians would have to suffer more death and casualties before surrender.  A ground invasion would result in excessive American casualties as well.

Option 3: Demonstration of the Atomic Bomb on an Unpopulated Area

Another option was to demonstrate the power of atomic bomb to frighten the Japanese into surrendering.  An island target was considered, but it raised several concerns.  First, who would Japan select to evaluate the demonstration and advise the government?  A single scientist?  A committee of politicians?  How much time would elapse before Japan communicated its decision—and how would that time be used?  To prepare for more fighting?  Would a nation surrender based on the opinion of a single person or small group?  Second, what if the bomb turned out to be a dud?  This was a new weapon, not clearly understood.  The world would be watching the demonstration of a new weapon so frightening that an enemy would surrender without a fight.  What if this “super weapon” didn’t work?  Would that encourage Japan to fight harder?  Third, there were only two bombs in existence at the time.  More were in production, but, dud or not, was it worth it to expend 50% of the country’s atomic arsenal in a demonstration?

In May 1945, Truman had formed the Interim Committee, a committee to advise the president about matters pertaining to the use of nuclear energy and weapons.  The Committee’s first priority was to advise on the use of the atomic bomb.  After prolonged debate, the president received the Committee’s historic conclusion:  “We can propose no technical demonstration likely to bring an end to the war.  We can see no acceptable alternative to direct military use.”

Option 4: Use of the Atomic Bomb on a Populated Area

Truman and his advisors concluded that only bombing a city would make an adequate impression.  Any advance warning to evacuate a city would endanger the bomber crews; the Japanese would be forewarned and attempt to shoot them down.  The target cities were carefully chosen.  First, it had to be a city that had suffered little damage from conventional bombing so it couldn’t be argued that the damage came from anything other than the atomic bomb.  Second, it must be a city primarily devoted to military production.  This was complicated, however, because in Japan, workers homes were intermingled with factories so that it was impossible to find a target that was exclusively military.  Finally, Truman stipulated it should not be a city of traditional cultural significance to Japan, such as Kyoto.  Truman did not seek to destroy Japanese culture or people; the goal was to destroy Japan’s ability to make war.

So, on the morning of August 6, 1945, the American B-29 bomber, the Enola Gay, dropped the world’s first atom bomb over the city of Hiroshima.  

What Happened in Japan That Day

The temperature near the blast site reached 5,400 degrees Fahrenheit.  The sky seemed to explode.  Birds ignited in midair; asphalt boiled.  People over two miles away burst into crumbling cinders.  Others with raw skin hanging in flaps around their hips leaped shrieking into waterways to escape the heat.  Men without feet stumbled about on the charred stumps of their ankles.  Women without jaws screamed incoherently for help.  Bodies described as "boiled octopuses" littered the destroyed streets.  Children, tongues swollen with thirst, pushed floating corpses aside to soothe their scalded throats with bloody river water.

One eyewitness at Hiroshima recalled, “I climbed Hikiyama Hill and looked down. I saw that Hiroshima had disappeared.... I was shocked by the sight.... Of course I saw many dreadful scenes after that — but that experience, looking down and finding nothing left of Hiroshima — was so shocking that I simply can't express what I felt.... Hiroshima didn't exist — that was mainly what I saw — Hiroshima just didn't exist.”

Approximately 80,000 people were killed as a direct result of the blast, and another 35,000 were injured.  At least another 60,000 would be dead by the end of the year from the effects of the atomic fallout.  

What Happened in America That Day

The President released a press release, which read in part, “Sixteen hours ago an American airplane dropped one bomb on Hiroshima and destroyed its usefulness to the enemy. ….  If they do not now accept our terms they may expect a rain of ruin from the air, the like of which has never been seen on this earth.”

A 21-year-old American second lieutenant recalled, “When the bombs dropped and news began to circulate that [the invasion of Japan] would not, after all, take place, that we would not be obliged to run up the beaches near Tokyo assault-firing while being mortared and shelled, for all the fake manliness of our facades we cried with relief and joy.  We were going to live.  We were going to grow up to adulthood after all.”


One week later, on August 14, 1945, after the second atomic bomb was dropped on Nagasaki, the Japanese surrendered.  World War II, the deadliest conflict in human history, with between 50 and 85 million fatalities, was finally over. 

What Did Harry S Truman Have to Say About His Decision to Use the Atomic Bomb?

At the time, the president seemed conflicted over his decision.  The day after the Hiroshima bomb was dropped, Truman received a telegram from Senator Richard B. Russell of Georgia, encouraging the president to use as many atomic bombs as possible on Japan, claiming the American people believed “that we should continue to strike the Japanese until they are brought groveling to their knees.”  Truman responded, “I know that Japan is a terribly cruel and uncivilized nation in warfare but I can't bring myself to believe that because they are beasts, we should ourselves act in that same manner.  For myself I certainly regret the necessity of wiping out whole populations because of the ‘pigheadedness’ of the leaders of a nation, and, for your information, I am not going to do it unless absolutely necessary.”

On August 9, the day the Nagasaki bomb was dropped, Truman received a telegram from Samuel McCrea Cavert, a Protestant clergyman, who pleaded with the president to stop the bombing “before any further devastation by atomic bomb is visited upon her [Japan’s] people.”  Two days later, Truman replied, “The only language they seem to understand is the one we have been using to bombard them.  When you have to deal with a beast you have to treat him as a beast.”

Looking back, President Truman never shirked personal responsibility for his decision, but neither did he apologize.  He asserted that he would not use the bomb in later conflicts, such as Korea.  Nevertheless, given the same circumstances and choices that confronted him in Japan in 1945, he said he would do exactly the same thing.

It was heavy burden to bear.  Speaking of himself as president, Truman said, “And he alone, in all the world, must say Yes or No to that awesome, ultimate question, ‘Shall we drop the bomb on a living target?’”  Every president since Harry Truman has had that power.  None has exercised it.

Last updated: January 11, 2023